U.S. Pat. No. 4,926,973, issued May 22, 1990 describes a lift designed to raise a person in a wheelchair from a passenger platform up to a rail car door and vice versa. The lift may also be used in other environments. The disclosure of that patent is incorporated herein by reference.
The patented lift is extremely light and easy to handle because of the extensive use of aluminum in the construction thereof. It is also portable since when the platform is in a lowermost position, the frame is raised and ground engaging wheels under the platform enable the entire device to be moved from one location to another.
The prior lift uses a manual cranking drive system which includes a braking system that is activated by the load on the wheelchair deck so that the manual effort required to crank the lift downwardly is proportional to the load on the deck.
The present invention is concerned with a novel drive and braking system for such a device.